1. Field of Invention
The present invention relates to combination locks and more particularly to a combination lock capable of being opened by inserting a key into keyhole in addition to turning tumbler wheels to a set series of numbers.
2. Related Art
Combination locks are well known. A type of combination lock capable of being opened by inserting a key into keyhole in addition to turning tumbler wheels to a set series of numbers is also known. One main design problem presents itself with locks of this type is that it requires one hand to hold the housing and the other hand to insert a key into keyhole and then turn a mechanism for opening. This is not convenient. Thus, continuing improvements in the exploitation of combination lock of this type are constantly being sought.